DEPARTMENT OF THE INTERIOR TO ACCOMPANY MAP MF-1573-A UNITED STATES GEOLOGICAL SURVEY

MINERAL RESOURCE POTENTIAL OF THE MAZATZAL WILDERNESS AND CONTIGUOUS ROADLESS AREA GELA, MARICOPA, AND YAVAPAI COUNTIES, ARIZONA

SUMMARY REPORT

By Chester T. WruckeL Sherman P. Marsh1, Clay M. Conway1, Clarence E. EHis , Dolores M. Kulik f Calvin K. Moss , and Gary L. Raines

STUDIES RELATED TO WILDERNESS Under the provisions of the Wilderness Act (Public Law 88-577, September 3, 1964) and the Joint Conference Report on Senate Bill 4, 88th Congress, the U.S. Geological Survey and the U.S. Bureau of Mines have been conducting mineral surveys of wilderness and primitive areas. Areas officially designated as "wilderness," "wild," or "canoe" when the act was passed were incorporated into the National Wilderness Preservation System, and some of them are presently being studied. The act provided that areas under consideration for wilderness designation should be studied for suitability for incorporation into the Wilderness System. The mineral surveys constitute one aspect of the suitability studies. The act directs that the results of such surveys are to be made available to the public and be submitted to the President and the Congress. This report discusses the results of a mineral survey of the Mazatzal Wilderness (NF3048) and Mazatzal Wilderness Contiguous Roadless Area (3-016) in the Tonto and Coconino National Forests, Gila, Maricopa, and Yavapai Counties, Arizona. Mazatzal Wilderness was established by Public Law 88-577, September 3, 1964. The contiguous roadless area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979.

SUMMARY Small quantities of gold, silver, and copper have been produced from the Mazatzal Wilderness. The wilderness has a high potential for gold, silver, and lead resources in veins in the vicinity of the Story mine, a high potential for silver and copper resources in vein deposits near Copper Mountain, a moderate potential for silver, gold, and copper in vein deposits in one area along the eastern border, and a high potential for copper in vein deposits at Mineral Creek. The Copper Mountain area, the area of silver, gold, and copper vein deposits along the eastern border, and the Mineral Creek area also have a low potential for copper in massive sulfide deposits. Two additional areas in the eastern and northern parts of the wilderness have a low potential for copper in vein and massive sulfide deposits. The wilderness has a high potential for copper in massive sulfide deposits and a moderate potential for copper in carbonate veins at Copper Camp Creek. An area east of the Mazatzal Wilderness has a high potential for gold resources in rocks that also occur in the wilderness, though no gold was found in these rocks in the wilderness. Three areas in the southern part of the wilderness have high, moderate, and low potential for mercury resources. A low potential for molybdenum exists west of the wilderness in three areas, two of which extend into the roadless area and the wilderness. The central part of the wilderness has occurrences of tin, but little evidence of a resource potential for tin. Two areas southwest of the wilderness have low and moderate potential for uranium, and one of these areas extends into the roadless area and the wilderness. No evidence of a potential for fossil fuels was identified in this study.

INTRODUCTION Physiography The Mazatzal Wilderness and the contiguous roadless The Mazatzal Mountains constitute the dominant area are located in the Tonto and Coconino National Forests, physiographic feature of the wilderness. The eastern slopes west and southwest of Payson, and are almost exactly in the of these mountains rise steeply from about 3,500 ft in geographic center of Arizona (fig. 1). This is a region of altitude along the valley of Rye Creek east of the range to relatively small mining districts and few mines, but 7,903 ft at Mazatzal Peak. To the west, the range slopes occurrences of many different metals are widespread. This steeply from the crest, then more gently along the lower report documents the geology, mining activity, and mineral flanks to the Verde River, one of the main drainage channels potential of the Mazatzal Wilderness and adjacent areas and of Arizona. In the northern part of the wilderness, the East discusses long-known, as well as newly discovered, mineral Verde River, a tributary of the Verde, occupies a deep canyon occurrences and the possibility of undiscovered mineral that separates the Mazatzal Mountains from mesas to the resources. north. The lowest parts of the wilderness have altitudes of Investigations summarized in this report were about 2,200 ft and are located near Bartlett Reservoir in the conducted in the field by the U.S. Bureau of Mines and the southwestern part of the area studied. U.S. Geological Survey, principally in 1979-1980. A few areas were studied briefly in 1981 and 1982. The Bureau of Mines Geologic setting examined mines, prospects, mineral claims, and mineralized areas and searched mining records. The Geological Survey The Mazatzal Mountains lie at the margin of the Basin conducted geologic mapping, geochemical sampling, remote- and Range physiographic province in a region of Arizona sensing studies, and geophysical examinations. where the mountain ranges are about as wide as or wider than

*U.S. Geological Survey 2 U.S. Bureau of Mines the intervening basins. The Mogollon Rim, which defines the River sequence. It is thought to be older than the Early southern physiographic border of the Colorado Plateau, is Proterozoic Alder Formation and has lithologic similarities about 5 mi north of the Mazatzal Wilderness. Paleozoic to the older (1,740-1,760 m.y.) Yavapai Series in the rocks, extensively exposed along the Mogollon Rim, have been Jerome-Prescott region (Anderson and others, 1971; L. T. largely eroded from the wilderness and roadless areas. The Silver, oral commun., 1982). A correlation with the Yavapai few remaining masses of Paleozoic rocks in the wilderness Series is not clearly established. rest on thick sequences of mostly steeply tilted stratified Proterozoic rocks of two stratigraphic sequences, each Proterozoic rocks and on Proterozoic granitic rocks. These about 3,300 ft thick, crop out near the confluence of the rocks are similar to Proterozoic layered and intrusive rocks Verde River and East Verde River in the northwestern part of exposed widely in central Arizona east and northwest of the the wilderness. One sequence, consisting of siltstone overlain wilderness. Tertiary volcanic rocks exposed within the by rhyolite conglomerate, rhyolite, and andesite is exposed in wilderness are at the southern end of a large volcanic field the Limestone Hills and rests in apparent conformity on the that extends north and northwest for more than 100 mi in the East Verde River sequence described above. The second western parts of the Colorado Plateau and adjacent areas of sequence occurs to the west in the vicinity of Squaw Butte the Basin and Range province. and is composed of graywacke, quartzite, and rhyolite. A contact between the two sequences has not been found. Both Mining activity of these sequences have rocks similar to the upper part of the Alder Formation and the overlying rhyolite, and to the Prospecting has been conducted intermittently in the rhyolite that is widespread in the eastern part of the Payson area, including the Mazatzal Wilderness, since the wilderness beneath quartzite. Both sequences are weakly discovery of gold near Payson in the 1870's. Within the metamorphosed to the greenschist facies and are largely wilderness and contiguous roadless area, gold and silver were unfoliated. the object of prospecting activity before World War n (Lausen Diorite, gabbro, and minor syenite of Early and Wilson, 1925) and may have been mined in small Proterozoic age occur as small intrusive masses in the quantities from several deposits. Few records are available Proterozoic stratified rocks in the Limestone Hills in the for this period. Sporadic exploration for precious and base northwestern part of the wilderness, and as a large complex metals since World War n has resulted in the production of east of the wilderness between Buckhead Mesa and Rye small amounts of copper, gold, and silver in the wilderness. Creek. These rocks contain a few large inclusions of Within a few miles of the southeast corner of the wilderness, metasedimentary rocks in the eastern part of the area outside mercury was produced at several mines from 1913 to the the wilderness. 1960's (Beckman and Kerns, 1965), and exploration continued Sedimentary and volcanic rocks of the Alder at a low level of activity to 1979. Ore containing copper, Formation, including felsic porphyry sills, are exposed in a gold, and silver was mined in areas immediately east of the tightly appressed syncline along the southern margin of the wilderness in the period 1938-1956. Uranium occurrences area. The formation comprises weakly to strongly foliated near Bartlett Reservoir were revealed in drill cores in the sandstone, graywacke, shale, conglomerate, rhyodacite and 1970's. Exploration for gold was being conducted a few miles rhyolite tuffs and flows, and subordinate mafic volcanic southwest of Payson in 1980. rocks. These rocks are metamorphosed to the greenschist facies of regional metamorphism. According to Ludwig GEOLOGY, GEOCHEMISTRY, AND GEOPHYSICS (1973), the formation is entirely volcanic or volcanogenic in PERTAINING TO MINERAL RESOURCE ASSESSMENT origin. He estimated the thickness of the formation to be about 18,000 ft. During the present study an additional 5,000 General Geology ft of strata were found in the wilderness beneath the rocks mapped by Ludwig. Ludwig (1973) described the Alder The geology of the Mazatzal Wilderness and contiguous Formation as conformably overlain by the Red Rock Rhyolite roadless area was mapped during this study and is shown on of Wilson (1937, 1939), a thick (more than 3,000 ft) sequence the accompanying l:48,000-scale map and on figure 2. The of alkali rhyolite, predominantly ash-flow tuff. The Alder only previous description of the geology in the wilderness Formation is in contact with other Proterozoic rocks of the (Wilson, 1939) is of the Proterozoic rocks in higher parts of area only along the northeast-trending Sheep Mountain the Mazatzal Mountains between Cactus Ridge and North fault. Lithologically the Alder Formation is dissimilar to the Peak. Ludwig (1973) mapped the geology of the mercury East Verde River sequence, and regional relations suggest district, which is mainly outside the wilderness south of that the Alder Formation is younger. Cactus Ridge. Part of this mapping is included in the The central part of the Mazatzal Wilderness is geologic map that accompanies this report. underlain by a large complex of alkali granite and granophyre The oldest rocks of the Mazatzal Wilderness and the that intruded the East Verde River sequence and the gabbro- surrounding area consist of sequences of Early Proterozic diorite complex. Regional relations indicate that the granite sedimentary and volcanic stratified rocks intruded by gabbro, also is younger than the Alder Formation. Granophyre is diorite, and alkali granite. These rocks in turn are overlain widespread in the wilderness and was emplaced as huge sheet- depositionally by Early Proterozoic sedimentary strata. The like bodies high in the alkali granite complex. The granite aggregate thickness of the Proterozoic stratified rocks is contact dips shallowly northward beneath stratified rocks of 61,000 ft. The Proterozoic rocks locally are capped by the East Verde River sequence, which are intruded by dikes of Paleozoic strata or they are partly buried by Tertiary tourmaline-bearing rhyolite porphyry that probably are volcanic flows and interstratified sedimentary rocks. related to the alkali granite. The alkali granite is thought to The oldest of the Early Proterozoic rocks in the correlate with granite for which an apparent age of 1,730115 wilderness may be the structurally fragmented stratified m.y. was obtained by L. T. Silver (Conway, 1976) from a sequence of mafic volcanic flows, pillow basalts, sample collected 3.5 mi east-northeast of Payson. volcaniclastic rocks, graywacke, minor rhyolite, jasper, and A quartz monzonite porphyry crops out in a 2.5 mi siltstone exposed on the east flank of the Mazatzal area at Tangle Creek on the west border of the area, just Mountains, along the East Verde River, and on the south rim outside the wilderness and adjacent roadless area. This rock of Buckhead Mesa. This stratigraphic section is about 26,000 type appears to be more calcic than the associated alkali ft thick and is informally referred to here as the East Verde granite and differs in geochemical signature from the alkali

Anderson and others (1971) geographically restricted the Alder Group to its type locality in the Mazatzal Mountains. The unit is here reduced in rank to Alder Formation since it contains no formations. Furthermore, the age of the unit is here revised from Precambrian to Early Proterozoic based on Pb-U dates of 1,730 ±20 m.y. from metavolcanic rocks as reported by Ludwig (1973). granite in having anomalous amounts of molybdenum, boron, faults are the youngest Proterozoic structural features in the tungsten, thorium, niobium, and yttrium, and in having area studied. Many north- and northwest-trending faults are distinctive gravity and aeromagnetic signatures. The quartz of Tertiary age, and some of them merged with Proterozoic monzonite porphyry is thought to have intruded the alkali faults and reactivated them. The Tertiary faults appear to granite, but the relative ages of these intrusive rocks have have been aciive as early as middle Miocene and to have not been established, and it is not known if the quartz contributed to the development of Basin and Range monzonite is Proterozoic. topography and structures. A sequence of Early Proterozoic rocks underlying the higher parts of the Mazatzal Mountains consists of alkali Geology related to mineralization rhyolite ash-flow tuff overlain in turn by the Deadman Quartzite of Wilson (1939), the Maverick Shale of Wilson Many of the mineral occurrences in the Mazatzal (1939), and the Mazatzal Quartzite (Wilson, 1939). The close Wilderness appear to be related directly or indirectly to the spatial association of the rhyolite with the upper parts of the alkali granite. The granite and associated granophyre are tin alkali granite complex and the apparent chemical affinities of bearing. Cassiterite has been found in modern stream the rhyolite and granite suggest that the rhyolite may be the sediments in areas of greisen zones in the granitic terrane, extrusive roof-rock equivalent of the granite that intruded although it has not been identified in bedrock samples. The it. Similar thicknesses and lithologic and chemical greisen zones are composed of highly sericitized quartz-rich similarities suggest that this rhyolite and the Red Rock granitic rocks containing abundant quartz veins and locally Rhyolite, which crops out south of the Sheep Mountain fault, tourmaline and hematite. The presence of cassiterite and may be equivalent. This is compatible with the sequence in tourmaline and high values of tungsten, beryllium, boron, Tonto Basin (Conway, 1976), where a thick alkali rhyolite fluorine, and rare-earth elements in stream sediments in rests on the Alder Formation and is overlain by a great areas of greisen in the granitic terrane are indicative of thickness of quartzite that is similar to the Deadman and mineralization late in the crystallization history of the Mazatzal Quartzites. An obstacle to this idea, however, is granite. This mineralization was followed by deposition of the fact that the Alder Formation, thousands of feet thick tin, silver, copper, gold, arsenic, antimony, mercury, bismuth, south of Sheep Mountain fault, is apparently missing beneath lead, and zinc in northeast-trending veins. The genetic the rhyolite north of the fault. Conway (1976) and Wilson relationship of this mineralization to the alkali granite is (1939) suggested that the Deadman Quartzite of Wilson (1939) based on the presence of tin and mercurian, auriferous, and and the Mazatzal Quartzite correlate with quartzite at argentiferous sulfosalts in veins in both the granite and its Natural Bridge. Silver (1967; oral commun., 1976) dated a host metamorphic rocks and on the existence of the same rhyolite flow within the quartzite at Natural Bridge as 1,715 suite of trace elements (tin, boron, and niobium) in these ±15 m.y. veins as in the greisen zones in the alkali granite. Tourmaline Porphyritic quartz monzonite and pegmatite crop out and fluorite locally are abundant in the vein systems. The in the southwest corner of the area outside the wilderness and sulfide minerals contain silver, bismuth, arsenic, and other resemble granitic rocks of Middle Proterozoic (Ruin Granite) elements found in well-known tin mineralization systems in age that have been recognized in a wide area farther south in the world (Taylor, 1979). The northeast-trending faults that the Mazatzal Mountains. contain the veins displace rocks as young as the Mazatzal Cambrian and Devonian sandstone and carbonate rocks Quartzite and could have been active earlier. These once were more abundant throughout the wilderness, but they relationships indicate that a significant time interval may crop out today only in the Limestone Hills, along lower Pine have occurred between emplacement of the granite and the Creek, and, together with Mississippian and Pennsylvanian development of related vein mineralization, as has been strata, in upper Pine Creek. These rocks have a total described for tin granites elsewhere (Sainsbury and Reed, thickness of about 800 ft and are regarded as having been 1973; Jones and others, 1977). deposited in shallow seas at the western edge of the North Gold occurrences in diorite east of the Mazatzal American craton. Wilderness may be related to the alkali granite, but this Rocks of Tertiary age cover about one-half of the area association has not been firmly established. The gold deposits and record an intricate history of volcanism and occur on northwest-trending faults that have had movement sedimentation from the middle of the Miocene to about the presumably of Tertiary age since the gold mineralization. It middle of the Pliocene. Rocks emplaced during this time is not known if these faults existed in Proterozoic time, but interval include basalt flows and intertonguing sandstone, Proterozoic faults of northwest trend occur in the area. limestone, and gravel, forming a composite section as thick Secondary copper minerals occur in mafic volcanic as 2,000 ft. Dacite flows and tuffs occur locally in the rocks of the East Verde River sequence in the Eisenhauer Tertiary strata, and dacite porphyry exists as intrusive rocks Canyon area immediately east of the wilderness boundary. at Lion Mountain, Squaw Butte, and near the northwest This copper may have been derived from syngenetic copper in corner of the area. the volcanic host. The youngest rocks in the area are poorly consolidated The mafic volcanic rocks in the East Verde River Quaternary sand and gravel in pediment alluvium, terrace sequence accumulated in a marine environment favorable for gravels, and stream deposits. Quaternary travertine stratabound massive sulfide-type mineral deposits. Massive accumulated at a locality in lower Pine Creek, and landslide sulfide deposits occur in Proterozoic marine volcanic rocks at masses are found in many parts of the area. Jerome, Arizona (Anderson and Nash, 1972). Although no The rocks of the Mazatzal Wilderness record a long deposits of this type have been discovered in the area, the and complex structural history (Wilson, 1939; Conway and favorable rocks and the widespread copper vein deposits others, 1982). The oldest deformation that affected rocks in suggest that massive sulfide bodies may exist in the East the area was the northwestward to northward tilting of the Verde River sequence and could be the source of the Proterozoic stratified rocks of the East Verde River secondary copper in Eisenhauer Canyon and elsewhere along sequence. The Alder Formation may have been deformed at the east and north sides of the Mazatzal Mountains as far this time, although the relative ages of the deformation northwest as Copper Mountain. experienced by these rocks and the stratified sequences along Copper occurrences in the same mafic volcanic unit the East Verde River are unknown. The next recorded event from the Casterson mine to the House mine are spatially was the emplacement of the alkali granite and associated associated with apophyses of granitic rocks and include granophyre into the roof rhyolite. After deposition of the significant amounts of gold, silver, arsenic, mercury, and Deadman Quartzite, Maverick Shale, and Mazatzal Quartzite, antimony, suggestive of a genetic relation to the this sedimentary sequence and, locally, the underlying rocks hydrothermal system in the alkali granite. However, some of were folded into a northeast-trending syncline and broken by this copper may have come from the mafic volcanic host. thrust faults along which movement was to the northwest. These deposits were mined for their precious metal content Prominent northeast- to north-trending faults, including the with copper as a byproduct. arcuate Deadman and Sheep Mountain faults, formed Primary and secondary copper minerals occur in mafic subsequently, as did some northwest-trending faults. These volcanic rocks in the Mineral Creek area near intrusive rhyolite related to the alkali granite. These minerals appear of approximately 1 to 2 mi 2 . Selected rock samples also were to be concentrated along faults that form a complicated taken from areas of altered outcrops and from existing pattern at the intersection of the Proterozoic Deadman and mining areas to determine mineral suites and trace-element Tertiary East Verde fault zones. There is a weak expression signatures of mineralized systems. in this area of the suite of elements related to the The samples were screened and the minus-80-mesh mineralization associated with the alkali granite. However, fraction of the sediment and the nonmagnetic heavy (*2.6 the location of copper minerals on or near Tertiary faults specific gravity) fraction of the concentrate were analyzed argues for remobilization. for 31 elements by a semiquantitative emission Primary and secondary copper minerals with small spectrographic method (Grimes and Marranzino, 1968). Rock amounts of gold, silver, and mercury occur at mines and samples were pulverized and also analyzed by prospects in the Copper Mountain area. These occurrences semiquantitative emission spectrographic methods. The may represent extensions of vein systems in the granite. resulting analyses along with statistical data for the Mazatzal Widespread copper minerals in the mafic volcanic rocks and Wilderness and contiguous roadless area are listed in two gossan interpreted as clasts in the graywacke are suggestive reports by Marsh and others (1983). of earlier, syngenetic copper. Semiquantitative spectrographic analyses of the Abundant veinlets of secondary malachite are nonmagnetic fraction of the heavy-mineral concentrates from associated with stratiform lenses of gossan and chert at stream sediments proved to be the most useful in evaluating Copper Camp Creek in the wilderness south of Sheep the Mazatzal Wilderness and contiguous roadless area and Mountain fault. Primary sedimentary structures in the gossan have provided the principal evidence for mineral systems and clasts of gossan in associated conglomerate attest to a related to the Proterozoic alkali granite and the quartz syngenetic origin of the primary minerals and suggest that a monzonite prophyry in the Mazatzal Wilderness and massive sulfide body may occur in the Copper Camp Creek surrounding areas. This sample medium contains the common area. Extensive well-developed chlorite beneath the chert ore-forming sulfide and oxide minerals as well as barite and and gossan lenses is indicative of hydrothermal alteration and other nonmagnetic minerals (zircon, apatite, fluorite, venting in the immediate vicinity. But here, as in copper cassiterite, rutile, and some sphene and tourmaline). The deposits associated with mafic volcanic rocks immediately concentrate medium also provides data that give a greatly east of the wilderness, elements such as arsenic, antimony, enhanced anomaly pattern, as all of the more common (low bismuth, gold, silver, and mercury, typical of the specific gravity, less than 2.6) rock-forming minerals (quartz hydrothermal system related to the alkali granite, are present and feldspar) that tend to dilute the anomalies have been and suggest an epigenetic overprint. removed. Mercury deposits of the Sunflower district east of the Several suites of geochemically associated elements southern part of the Mazatzal Wilderness are in steeply found in samples collected during this study were discussed dipping highly foliated strata of the Alder Formation and earlier as having formed during two or more episodes of contain cinnabar near the surface and mercurian tennantite, mineralization. In addition, chromium and nickel were tourmaline, and cinnabar at depth (Lausen and Gardner, 1927; identified in stream sediments and in panned stream-sediment Faick, 1958; Ransome, 1915). The mercurian sulfides and concentrates from of Tertiary basalts that have not been tourmaline suggest an affinity to the sulfide mineralization in mineralized. The highest concentrations of these elements the Proterozoic alkali granite. The cinnabar may have form sharply defined geochemical map patterns at the east evolved from the breakdown of preexisting sulfides probably edge of the wilderness from the East Verde River north and in during Tertiary volcanism. Cenozoic basalt, apparently the west-central part of the Mazatzal Wilderness northeast of intrusive into the Alder Formation, occurs near Highway 87 Horseshoe Reservoir. The source of the elements is thought immediately south of the Sunflower district, and Miocene to be a chromian pyroxene that formed the bulk of the volcanic rocks occur to the west in the wilderness. concentrate samples taken from areas draining the basalts. Aeromagnetic data suggest a possible buried intrusive body in In an evaluation of uranium resource potential in the vicinity of the mercury district. conglomerate of several Proterozoic formations in central The quartz monzonite porphyry at Tangle Creek, Arizona, Anderson and Wirth (1981) obtained data on the immediately west of the Mazatzal Wilderness and contiguous concentration of uranium in the Deadman Quartsite of Wilson roadless areas, was identified during this study as (1939) and the Mazatzal Quartzite. Except for local minor mineralized, although no prospects or mines were found. enrichments of uranium (as much as 33 ppm) in hematite-rich Unusual concentrations of molybdenum, bismuth, tungsten, conglomerate near the base of the Deadman, no significant uranium, thorium, and scandium were found in a narrow zone sedimentary concentration of uranium was found in these from the west side of Tangle Creek outside the wilderness quartzites in the Mazatzal Wilderness. Anderson and Wirth and roadless area, north into the roadless area. Anomalous (1981) identified no resource potential. molybdenum and uranium concentrations in stream waters from the quartz monzonite porphyry at Tangle Creek were Remote sensing the highest found in the area. The geochemical suite and data from water analyses are suggestive of porphyry As part of this study, limonitic materials were molybdenum mineralization. identified in images of the Mazatzal Wilderness area using a Uranium in Tertiary tuffs and sedimentary rocks along color-ratio-composite method (Rowan and others, 1974). This the Verde River could have been derived from the siliceous technique combined with field data was used to map areas of tuffaceous debris they contain or from nearby Proterozoic hydrothermal alteration associated with limonitic materials granitic rocks. The granites of the area contain anomalous and to help define mineralized systems. The term limonite, concentrations of uranium and were exposed when the as defined by Blanchard (1968), is used as a general term for sedimentary rocks accumulated. hydrous iron oxides but is modified to include any material A small occurrence of copper-stained quartz, locally with the unique spectral reflectance properties of the ferric considered a gem stone because it resembles turquoise, oxide minerals such as hematite and goethite as defined by occurs in freshwater limestone and siltstone low on the east Hunt (1980). The minerals pyrite and (or) hematite are flank of Chalk Mountain. almost universally associated with hydrothermal alteration potentially related to mineralization and these minerals Geochemistry weather to produce limonite, which is detected by this technique. Areas of hydrothermal alteration that are totally Three sample media were selected as best for lacking limonitic materials will not be detected by this geochemical sampling in the arid high desert environment of technique; however, such areas missed by this approach are the Mazatzal Wilderness: stream sediment, heavy-mineral believed to be insignificant in the Mazatzal area. A more concentrates from stream sediment, and rock. Sediments and significant problem in the Mazatzal area was the presence of concentrates were collected from first- and second-order greater than 40 percent vegetation cover, which severely stream drainages at 472 localities in the wilderness and hindered the ability to map the distribution of limonitic rocks contiguous roadless areas, each drainage representing an area and soils by this technique. This vegetation problem was signficant for much of the wilderness where small scattered distribution of the Proterozoic alkali granite at the surface areas of limonite surrounded by areas of high vegetation and of its inferred probable distribution in the subsurface. In cover were observed. These small limonitic areas are particular, low gravity readings suggest that the granite generally not related to mineralization but to exposed underlies the rhyolite and overlying quartzites and shale in portions of known limonitic lithologies. the vicinity of Mazatzal Peak in the east-central part of the This vegetation problem, however, does not appear to wilderness, and that it may underlie the Tertiary basalt cover be significant for the alkali granite, which includes the north of the East Verde River. Relatively high gravity values largest limonite anomaly. This large anomaly is are associated with the Alder Formation south of the gravity characterized in a 1:250,000-scale color-ratio-composite gradient that follows the Sheep Mountain fault. This image as an area of pervasive limonite staining, as opposed to association suggests that alkali granite, if present, is very the other part of the alkali granite, which, as seen in the deep. This gradient extends to the Verde River along the image, has small scattered limonitic areas. These small projection of the fault and suggests a westerly extension of limonitic areas are apparently due to limonite after mafic the Alder Formation beneath Tertiary rocks. A positive minerals in the granite. The large limonite anomaly is gravity anomaly in the Tangle Creek area lies over exposures spatially associated with the tin mineral suite and is believed of the quartz monzonite porphyry and is partially coincident to define the extent of iron oxidation metasomatism with the nose of the high-level aeromagnetic high that trends associated with the tin mineralization. Inspection on the southeastward into the wilderness at the assumed projection Landsat images of this same granite surrounding the Mazatzal of an extensive intrusive mass, which includes the porphyry. Wilderness indicates that the iron metasomatism is not a The fact that the gravity anomaly in the Tangle Creek area is universal characteristic of the granite and that the single not coincident with the highest part of the magnetic anomaly largest area of iron metasomatism, which is spatially related west of the nose further suggests different geophysical to tin greisen, is within a part of this granite. responses to various phases of the larger intrusive body. The gravity and aeromagnetic patterns north of Tangle Creek Geophysics along the west border of the roadless area also may reflect different phases of the quartz monzonite and related rocks. Aeromagnetic maps and a gravity map were made for A positive gravity anomaly outside the east edge of the this study. The aeromagnetic maps contain data from a low- wilderness is caused by a large diorite body and the level survey, flown at 1,000-ft terrain clearance, and a high- metamorphic mafic volcanic rocks to the west. level survey flown at a constant altitude of 9,000 ft (Sauck and Summer, 1970). In addition, electromagnetic data were BONING DISTRICTS AND MINES gathered in the Copper Camp Creek area in the southern part of the Mazatzal Wilderness during this study. The Mazatzal Wilderness and contiguous roadless area The low-level and the high-level aeromagnetic data are located between the main parts of the Green Valley are complementary in this study in that data from the low- (Payson), Mazatzal Mountains, Sunflower, and Magazine level survey show the effects of rocks at and near the mining districts (Wilson and others, 1961; Mardirosian, surface, and data from the high-level survey reflect control 1973). Most mines and prospects in the wilderness lie in or by deeper seated bodies. adjacent to the Green Valley (Payson) district. Mineral The complex patterns of the small aeromagnetic highs deposits at the southeast corner of the wilderness are in the and lows in the low-level survey are caused principally by Sunflower and Mazatzal Mountain districts. Claims at Tertiary basalt. Aeromagnetic highs in the Sunflower mining Horseshoe Dam and east of Chalk Mountain have been district in the southeastern corner of the area, where the recorded as belonging to the Magazine mining district. At basalt is absent, follow the grain of the Alder Formation, and the time of this investigation, no mining or claim activities several highs along the East Verde River in the north-central were observed in the wilderness or contiguous roadless area part of the wilderness probably reflect Proterozoic gabbro, with the exception of the area around McFarland Canyon which lies in part beneath the basalt. Wherever alkali granite (Marsh, 1983). and the overlying thick sections of rhyolite and quartzites are preserved, relatively low magnetic values occur. Green Valley (Payson) district The high-level aeromagnetic survey also shows low magnetic relief in areas of alkali granite and the overlying Claims, prospects, and mines in the part of the rhyolite-quartzite section. A prominent high, centered west Mazatzal Mountains that lies in the wilderness are thought to of Tangle Creek at the center of the western margin of the be outside of formal mining districts, but most are informally area, projects southeastward into the Mazatzal Wilderness. associated with the Green Valley, or Payson, district. The This anomaly is thought to result from an intrusive body that Blue Lode, Los Conquistadores, and Stingy Lady prospects is concealed by Tertiary basalt and sedimentary rocks in the west of the crest of the Mazatzal Mountains may be part of wilderness and may be related to the quartz monzonite the district. Assay and geochemical data indicate that these porphyry exposed at Tangle Creek. A high-level properties were explored chiefly for silver. These properties aeromagnetic anomaly at the southeast corner of the area, almost certainly were first worked before World War n, outside the wilderness, extends northwestward into the perhaps long before then, as trails leading to them are Sunflower mercury district and is not explained by any obscure; there are no roads today. Numerous mines and exposed rocks. This anomaly may be caused by a buried prospects in the area between Copper Mountain and Red intrusive mass. The spatial distribution of mercury deposits Metal Tank also are informally considered to be in the Green in the Sunflower district suggests a possible genetic Valley (Payson) district. Claims located for silver in this area relationship between mineralization and the inferred postdate World War n. Exploration for silver and copper 1 mi intrusion. Aeromagnetic anomalies of high relief at the southwest of Copper Mountain during the period 1964 to 1967 eastern edge of the area outside of the wilderness, and two resulted in an open cut about 110 ft by 60 ft and 100 ft high anomalies in the north-center of the wilderness are deep. This property was mined in 1967. Several miles of interpreted as resulting from Proterozoic gabbro and bulldozer roads were made during the exploration and mining. diorite. The aeromagnetic gradient reflected by The Casterson, Collom, Crackerjack, House, and southward-rising magnetic values in the southern part of the Gowan mines are in the Green Valley (Payson) district. These high-level map may be related to a large Proterozoic granitic mines may date from the early days of mining in the area, but pluton. there are few records. A photograph in an early report An electromagnetic survey was conducted at Copper (Lausen and Wilson, 1925) shows a stope that was dug at the Camp Creek across a small part of the mineralized zone using Gowan mine in the 1880's. The House and Collom mines are 1 an instrument especially designed to detect massive sulfide mi east of the wilderness boundary. Portals of two adits of bodies. No evidence of a massive sulfide body was found the Casterson mine are east of the boundary, but the above the maximum search depth of about 400 ft. workings extend into the Mazatzal Wilderness and the block The gravity data for most of the Mazatzal Wilderness of claims at the mine straddle the wilderness boundary (Ellis, show relatively low values indictive of the widespread 1982). At the time of the study, workings of the Collom and Casterson mines were accessible, but mineralized parts of the to indicate that geologic processes acted to House mine could not be reached. produce a mineral resource. Numerous roads and bulldozer cuts at Mineral Creek, north of the Collom mine, are the result of exploration work Moderate potential. The available information defines by at least six mining companies during the period 1957 to a geologic environment that is favorable for 1977. This work was conducted chiefly on the ridge north of mineral resources, and there is evidence to Mineral Creek on both sides of the wilderness boundary. support the interpretation that geologic Bulldozer roads also were made in Eisenhauer Canyon in 1957 processes could have resulted in a mineral in an area that has a few prospects and several short adits resource. (Ellis, 1982) and now is inside the wilderness. High potential. The available information defines a Sunflower and Mazatzal Mountains districts geologic environment that is favorable for mineral resources, and there is sufficient Early reports described the Sunflower district as evidence to support the interpretation that including the mercury deposits that now lie east of the geologic processes resulted in a mineral southern part of the wilderness (Ransome, 1915; Lausen and Gardner, 1927). Subsequently, mines of the area have been considered to be in the Mazatzal Mountains mining district Available information used in evaluating mineral potential (Beckman and Kerns, 1965; Bailey, 1969). Informal usage includes the results of geologic, geochemical, or geophysical would include the Sunflower district as part of a larger studies and the results of investigations of mines, claims, and Mazatzal Mountains district. The Story mine and the deposits production records. Geologic environment refers to the rocks at Copper Camp Creek are located in the wilderness 0.75 mi and the structural features of the rocks in a geographically and 3 mi, respectively, west of the nearest mercury mine and restricted setting and includes any materials that may have informally are associated with these districts. been added during mineralizing events. Geologic processes The Story mine was developed in a gold-silver-lead are those naturally occurring systematic actions that result in deposit located east of Saddle Mountain and less than 1,000 ft the development of rocks and minerals or that cause changes inside the Mazatzal Wilderness boundary. A shaft and two in them. A mineral resource is a concentration of naturally adits on the property are caved. occurring solid, liquid, or gaseous material in or on the A few adits, prospect pits, and a shaft are located in Earth's surface in such form and amount that economic McFarland Canyon north and northeast of the Story mine in extraction of a commodity from the concentration is rocks that show evidence of gold-pyrite-arsenopyrite currently or potentially feasible (U.S. Bureau of Mines and mineralization. The workings appear to be old, as no roads U.S. Geological Survey, 1980). lead to them. At Copper Camp Creek, more than a dozen pits and Areas 1, 2, 3, 4, 5, 6, 7, and 8 silver, gold, and copper trenches, a shaft 60 ft deep, and an adit 390 ft long occur in a block of 22 claims known as the Copper Cliff group. These Areas favorable for silver, gold, and copper resources workings were dug to explore the occurrence of copper occur in metamorphic rocks in or near the northern, eastern, carbonate minerals that locally are abundant in surface and southern parts of the wilderness. At some localities in exposures. The age of the workings is unknown. the northern and eastern parts of the area, precious metals occur with substantial amounts of copper, but at other Magazine district localities copper alone is the principal metal. In the southern part of the wilderness, precious metals and copper, other than The Magazine mining district is centered southwest of in trace amounts, occur in separate deposits. The silver, the map area, about 7 mi west of Horseshoe Reservoir, in an gold, and copper deposits are small, and collectively they area of silver and copper deposits (Wilson and others, 1961; appear to constitute only a small resource of these metals. Moore and Roseveare, 1969). In the 1970's, two blocks of 150 Occurrences of silver at the Stingy Lady prospect northeast claims each were located on the east side of the Verde River of Midnight Mesa and copper at the Blue Lode and Los and were recorded as belonging to the Magazine district. The Conquistadores prospects in the west-central part of the claims extend from southeast of Horseshoe Dam, outside of wilderness are not indicative of resource potential for silver the Mazatzal Wilderness, north to the vicinity of Chalk and copper. Mountain, where some of the claims are in the roadless The different ratios of precious metals to copper in area. At least three holes have been drilled in the claims. the mineral deposits of these areas suggest a dual origin of Tertiary sedimentary rocks in the claimed area contain the copper and possibly of the precious metals as discussed abundant volcanic detritus and are uranif erous. earlier. Some of the gold, silver, and copper are interpreted as having been derived from the alkali granite, whereas part ASSESSMENT OF MINERAL RESOURCE POTENTIAL of the copper may have been mobilized from syngenetic copper concentrations, possibly including massive sulfide Geologic, geochemical, remote-sensing, and deposits, in Proterozoic volcanic and volcaniclastic rocks. geophysical data acquired during this study and information Gold and silver (with subordinate lead) in the southern part of obtained from the mining history, mineral exploration, and the area may have yet a different origin. assays indicate that the Mazatzal Wilderness and contiguous roadless areas have mineral potential for a number of Area 1 metals. Within the wilderness there is potential for gold, silver, copper, lead, uranium, mercury, molybdenum, and One of the principal areas of mineral resource possibly tin. One roadless area has potential for uranium and potential in the Mazatzal Wilderness is located near the molybdenum. southern border of the wilderness in metamorphic rocks of Areas of mineral resource potential are shown on the the Alder Formation and includes the Story mine and nearby accompanying l:48,000-scale map and on figure 3. The parts of McFarland Canyon. The Story mine was developed in criteria used to define the 18 areas shown are listed on the tuffaceous volcaniclastic rocks containing silver-gold-lead accompanying l:48,000-scale map and are discussed below. vein deposits. As stated earlier, all of the workings are The resource potential of mineralized areas in the caved, and the only existing records of mining activity date Mazatzal Wilderness, the contiguous roadless areas, and from after World War n. Lead arsenate minerals related to adjacent areas is ranked in this report using the following the mineralization are evident in surface exposures in and criteria: around the old workings, and a gossan vein can be followed discontinuously for several hundred feet, possibly crossing the Low potential. The available information defines a strike of the host rocks at a low angle. geologic environment that is permissive for Much of the area around the Story mine appears to be mineral resources, but there is little evidence weakly sericitized, and the rocks exhibit a bleached and altered aspect (Marsh, 1983). The area has been strongly suggestive of an exhalative process in the stratigraphically silicified and contains abundant quartz-chlorite veins. In higher part of the Alder Formation. However, the many places, the fine-grained tuffaceous host rocks have mineralization in McFarland Canyon postdates emplacement been silicified, but they retain much of their original of the rhyolite sheets, which were intruded after development character. In many of the quartz veins, included tuffaceous of foliation in the host rocks. The quartz veins are later still material appears to have been altered to chlorite, which in and are subparallel to layering of the strata. Had the quartz some areas is further altered to iron oxides. In some quartz veins formed in fractures that channeled rising hot solutions veins, sites once occupied by altered bedrock inclusions are during volcanism, some of the veins likely would extend now only voids. The altered area extends for at least 0.5 mi through the altered zones at large angles to the host strata radius around the Story mine, and the zone of silicification (Boyle, 1979, p. 301). extends much farther. The mineral deposits in the Story mine-McFarland Assay values and the old mining records from the Story Canyon area may have developed from an igneous source at mine show that the mine has about 78,000 tons of indicated depth, possibly an intrusive body related to the aeromagnetic resources containing 0.06 oz/ton gold, 1.9 oz/ton silver, and high discussed earlier as occurring in the mercury mining area 3.9 percent lead. These estimates are for resources east of the Story mine. Although mercury was detected in remaining after subtraction of recorded production but sulfides, no evidence of cinnabar was found at the Story mine include any unrecorded production that may have occurred. or in McFarland Canyon, and there is no evidence at present In McFarland Canyon, gold occurs with pyrite and indicating a connection between this mineralization and arsenopyrite in intrusive rhyolite sheets and in phyllitic, mineralization in the mercury district. partly tuffaceous shale and metasiltstone of the Alder Area 1 has a high potential for the occurrence of gold- Formation, from about 0.5 mi inside the Mazatzal Wilderness silver-lead resources. Considerable exploration would be to about 0.5 mi east of the wilderness boundary (Marsh, required to determine the extent and grade of mineralized 1983). The mineralized area is about 1,500 ft wide and is rocks in the area. parallel to the trend of the host rocks. The greatest concentrations of mineralized rock found in this area are Area 2 3,000 ft north of the Story mine and in an area about 1,500 ft in diameter centered 4,000 ft northeast of the Story mine. Silver and copper veins occur in the vicinity of Copper Several short adits, a shaft, and a few prospect pits are Mountain in the north-central part of the wilderness. This located in the area, but there is no record of production. area includes upper parts of the steep north-facing slope of Mineralization in the McFarland Canyon area resulted the canyon of the East Verde River south from Copper in disseminated pyrite and generally sparse, but locally Mountain and contains Bullfrog Ridge and the ridge that abundant, disseminated arsenopyrite in the rhyolite, and as trends northeasterly from Red Metal Tank. The area has a arsenopyrite veins in the rhyolite and more commonly in the large block of claims (Bills, 1982) and many mines and host sedimentary rocks. Arsenopyrite occurs as 0.75-1.5 in.- prospects, reflecting widespread mineralization. The veins wide veinlets either as selvages to quartz veins or alone. trend north-northeast and occur in a zone of intensely Veins are not abundant in the area. They can be followed 10 fractured rocks on both sides of a major fault of the same to 20 ft subparallel to bedding and appear to form parts of a trend. This fault separates Early Proterozoic mafic volcanic vein system that can be traced with interruptions for several rocks to the east from Early Proterozoic graywacke to the thousand feet along McFarland Canyon (D. M. Brown and J. L. west and cuts the alkali granite to the south. White, Texasgulf Western, Inc., oral commun., 1982). As at Mineral occurrences in the part of area 2 east of the the Story mine, weakly sericitized rock is widespread and is fault are mainly along Bullfrog Ridge and consist of silver- found in the rhyolite as well as the metasedimentary rocks. bearing copper sulfide and oxide minerals in volcanic rockj. The rhyolite and metasedimentary rocks are locally silicified, Geochemical samples collected from prospects in mineralized and the metasedimentary rocks contain quartz veins. rocks on the ridge and assay values from old workings show The rhyolite sheets follow the strike of the adjacent that the veins and the adjacent altered country rock are rich sedimentary rocks but are clearly intrusive, as the sheets in copper, silver, lead, and zinc, and that they contain trace locally cross the lithologic layering and foliation of these amounts of bismuth, cadmium, antimony, arsenic, and rocks. The rhyolite is unfoliated and thus postdates the mercury. This geochemical suite is typical of the Proterozoic deformation. hydrothermal mineralization related to the alkali granite, Geochemical data show that arsenic, gold, silver, lead, which crops out a short distance to the south and may and small amounts of copper occur in the mineralized area underlie the area at relatively shallow depth. The and that the highest values for gold are in places having high hydrothermal mineralization greatly overwhelmed any copper concentrations of arsenopyrite. This is the same suite of that may reasonably have been contributed by the mafic elements that was found at the Story mine. volcanic host. It is possible that massive sulfide deposits The origin of the mineral deposits at the Story mine exist in the volcanic rocks and could be the source of the and in McFarland Canyon is uncertain. The spatial copper in the vein deposits. association of rhyolite to the mineralized rocks in McFarland The graywacke west of the north-trending fault locally Canyon indicates a genetic relationship and might also is intensely altered and has abundant quartz veins. Iron oxide account for the mineralization at the Story mine, although no is abundant, and yellow and green complex secondary rhyolite is exposed in the immediate vicinity of the Story minerals coat fracture surfaces. No sulfide minerals were mine. An argument against a genetic tie between the found in these rocks. Geochemical data from the veins show rhyolite and the mineralization is that the rhyolite sheets and high concentrations of copper, silver, lead, and zinc, and adjacent host rocks are barren outside of McFarland Canyon. trace quantitites of antimony, arsenic, and tin. This suite of Genesis of the mineral deposits by volcanogenic elements also is indicative of the hydrothermal processes in the Story mine-McFarland Canyon area is mineralization that emanated from the alkali granite. suggested by the apparent stratabound distribution of the Silver and copper in quartz veins in the area occur at mineralized rock, its association with tuffaceous the open-cut mine located west of Bullfrog Canyon and 1 mi volcaniclastic rocks, and the widespread effects of southwest of Copper Mountain. This is the only place in the silicification and sericitization. The existence of a small Mazatzal Wilderness where copper and silver production has tongue of basalt on strike with the Story mine shows that been recorded. According to records of the U.S. Forest volcanism was closely contemporaneous with sedimentation in Service, this mine produced 33.5 tons of ore containing 938 Ib that area, and high concentrations of lead, abundant in many of copper and 485 oz of silver in 1967. Based on this distal massive sulfide deposits (Anderson and Guilbert, 1979), production and the presence of spotty but locally high-grade occur in the mineralized zone at the Story mine and in rock in the mine area, the deposit has a high potential for McFarland Canyon. Evidence of volcanogenic sulfides has additional resources of silver and copper. Geochemical been found in the lower part of the Alder Formation in the analyses and assays showing high concentrations of these Copper Camp Creek area, discussed later,- and interbedded metals in altered rock outside the mine are indicative of a jasper and sulfide-barren, but iron-rich carbonate rocks are high potential for the occurrence of silver and cooper resources elsewhere in area 2. The silver and copper of copper minerals is near the junction of the Dead man and resources could be expected to occur in a few deposits East Verde River faults. Rocks associated with the alkali containing hundreds to a few tens of thousands of tons of granite intruded graywacke south of Mineral Creek, and it is mineralized rock. The possibility for the recovery of copper likely that these intrusive rocks also underlie the mafic in the area may depend on the tenor of associated silver. The volcanic rocks in the Mineral Creek area. Geochemical data potential for the presence of massive sulfide resources in show a weak trace-element signature of hydrothermal area 2 is low. mineralization related to the alkali granite. However, much of the copper here could have been derived from the mafic Area 3 volcanic bedrock. Copper carbonate minerals in faults indicate some remobilization of copper as young as Tertiary. Veins containing silver, gold, and copper occur at the The resource potential for copper in mineralized veins House, Collom, and Casterson mines, which are located east and fractures in area 4 is high in an area 800 ft by 3,000 ft of the east border of the Mazatzal Wilderness in area 3. astride the Mazatzal wilderness boundary on the north side of Evidence from underground workings, surface Mineral Creek. This locality has the highest concentration of exposures, and dump materials show that mineral deposits in copper in area 4. The concentration is spotty, and copper area 3 consist of well-defined veins in mafic volcanic rocks of averages 0.09 percent (Ellis, 1982). There is a moderate the Proterozoic East Verde River sequence. Veins mapped at potential for the occurrence of copper resources in veins in the Collom and Casterson mines follow northerly and the mafic volcanic rocks outside the area of greatest exposed northwesterly trends (Ellis, 1982) and contain quartz and mineral concentrations. Area 4 also has a low potential for locally sulfide and oxide minerals. The deposits in area 3 copper resources in massive sulfide deposits. resemble those mineralized parts of area 2 near Copper Mountain that are underlain by mafic volcanic rocks. Like Area 5 the deposits of Copper Mountain, the alkali granite crops out near mineralized parts of area 3. These exposures are 1 mi Copper carbonate veins locally are abundant in area 5, northwest of the House mine and in the eastern part of the which is located at Copper Camp Creek in the southern part Casterson mine area. of the Mazatzal Wilderness. A shallow shaft, a short adit, Geochemical and assay data from samples collected at and numerous prospect pits and trenches have been developed mines in area 3 reveal low to high concentrations of silver, in the area in a block of 22 mining claims (Ellis, 1982). There gold, and copper. A geochemical sample containing is no record of production, and the amount of copper ore that secondary copper minerals collected from the dump at the might have been shipped would have been small (Ellis, 1982). House mine was found to contain>30 ppm silver, 13 ppm gold, Rocks in one of the more intensely mineralized parts of the >20,000 ppm copper, and high concentrations of arsenic, adit in this area averages 0.71 percent copper and 0.2 oz/ton antimony, bismuth, cadmium, lead, and zinc. A sample of silver (Ellis, 1982). As discussed earlier, an attempt during country rock from this dump was found to have the same this study to determine the presence of massive sulfides by elements in lower but still anomalous concentrations. geophysical means showed that such deposits are not present Samples from the dump of the Collom mine contain the same above the maximum search depth of 400 ft. suite of elements. The trace-element suite in these rocks Beds and lenses of impure gossan, locally about 6 ft therefore has the same geochemical signature as mineralized thick and interlayered with chert in the Alder Formation in rocks formed during the hydrothermal phase of the alkali- area 5 suggest an early mineralization of the stratabound granite. However, it is reasonable to assume that some of massive sulfide type in which volcanogenic sulfides were the copper in the mineral deposits of area 3, like the deposits deposited by sedimentary processes. Fragments of gossan in at Copper Mountain, may have been supplied by the mafic volcanic breccia interlayered with the chert resulted from volcanic host rocks, possibly massive sulfide deposits. breakup and transport of the gossan and provide additional The Casterson and Collom mines produced a few evidence of an early mineralization. The abundant malachite ounces of gold, about 300 oz of silver, and a few pounds of veinlets occur in the volcanic breccia and record a late copper in the early 1940's. Both mines probably had some mineralizing event. Significant concentrations of arsenic, production before these dates. There is no recorded antimony, bismuth, gold, silver, and tungsten in geochemical production from the House mine. The probable total samples of the malachite-bearing rocks suggest that the late production from all three mines was small. Combined mineralization may be an overprint by the hydrothermal inferred reserves of the Casterson and Collom mines are system related to the alkali granite, but it also is possible estimated to be 52,000 tons of mineralized rock containing that the veins formed from copper derived from massive 0.7 oz/ton silver and 0.07 oz/ton gold (Ellis, 1982). There is a sulfide mineralization. moderate potential for the presence of additional vein-type There is moderate potential for the occurrence of mineral resources in favorable geologic settings in other parts copper resources in carbonate veins and high potential for the of area 3, especially near granitic rocks, either exposed or at occurrence of copper in massive sulfide deposits in the shallow depths. If present they probably would occur in Copper Camp Creek area. deposits of high grade and small size and would measure from hundreds of tons to a few tens of thousands of tons of Areas 6 and 7 mineralized rock. The area has a low potential for resources of copper in massive sulfide deposits. Scattered and generally low concentrations of copper minerals occur in areas 6 and 7, located respectively in the Area 4 eastern and northern parts of the area studied. Area 6 is situated partly inside and partly outside the Mazatzal Copper minerals are widespread in area 4, which Wilderness Wilderness at the eastern border, near North trends approximately east-west for a distance of about 1.25 Peak. It includes all of the area underlain by mafic volcanic mi in the vicinity of Mineral Creek, north of North Peak, at rocks outside of area 3. Area 7 is situated entirely in the the eastern border of the Mazatzal Wilderness. Half of the wilderness northwest of area 6 and contains mafic volcanic area is inside the wilderness. A large block of claims rocks outside of area 2. centered east of the wilderness covers most of area 4 and Eisenhauer Canyon is the only part of area 6 showing extends into the wilderness (Ellis, 1982). possibly significant mineral occurrences. Mineral exploration At least six mining companies conducted mineral was conducted in the area in 1957. There is no record of exploration work in the area during the period 1957-1977. production. This work resulted in the construction of many roads and Mineral occurrences at Eisenhauer Canyon consist of bulldozer cuts, chiefly on the ridge north of Mineral Creek, secondary copper minerals, principally malachite, and quartz on both sides of the Mazatzal Wilderness boundary. concentrated in faults and fractures. The host mafic volcanic Mafic volcanic rocks in the Mineral Creek area have rocks are propylitized and contain abundant epidote. copper oxides on fracture surfaces and local concentrations Spectrographic and wet-chemical analyses of rocks and of secondary potassium feldspar. The greatest concentration stream sediments collected in the area show small amounts of copper, and assay data (Ellis, 1982) indicate that silver is there has been little production from the district since the present locally in low concentrations. Chemical elements 1960's. About half of the district, including two of the four indicative of mineralization related to the alkali granite are most productive mines the Pine Mountain and Sunflower not present. The copper is interpreted as having been mines are in the area studied. A small part of the district mobilized from the mafic volcanic bedrock, possibly from extends into the wilderness (fig. 3). stratabound sulfide deposits. A few occurrences of secondary copper minerals exist Area 9 in mafic volcanic rocks of area 6 outside of Eisenhauer Canyon and in area 7. They are small and widely separated, The major mercury mines in the northern part of the and only a few prospects have been found in them. The weak Sunflower mining district, and the strongest indications of mineral occurrences in these areas are thought to be of mercury in the area studied, are in area 9. This area begins copper that originally was syngenetic in the host volcanic at the eastern border of the Mazatzal Wilderness and extends rocks, which could contain massive sulfide deposits. No clear to the northeast in a belt about 5,000 ft wide. It includes evidence of massive sulfide deposits was found in areas 6 or many prospects as well as numerous mines (Ellis, 1982). 7. Mercury in area 9 occurs as cinnabar in shaly tuff and The scattered occurrences of secondary copper sandstone of the Alder Formation. The mercury occurs minerals in areas 6 and 7 suggest the mineral resources of intermittently along strike for 5 mi within a stratigraphic these areas are small, but if massive sulfide bodies exist the interval of about 5,000 ft on the north limb of a major copper resources could be large. Available data indicate that syncline. Mercury mines in this limb are coextensive with an areas 6 and 7 have a low potential for copper resources in irregular Proterozoic felsic sill of the Pine Mountain veins and a low potential for copper resources in massive Porphyry of Wilson (1939). Most mines occur near the margin sulfide deposits. of the sill; only a few prospects occur within it. Cinnabar is disseminated in the host rocks and is concentrated along Area 8 prominent foliation planes. The northwest-trending nose of an aeromagnetic high underlies the central part of area 9 and Gold is the principal commodity of area 8, which is may represent an unexposed intrusive body related to the located in the east-central part of the area studied, east of mercury mineralization. the Mazatzal Wilderness and contiguous roadless areas. Occurrences of mercury in area 9 extend beyond the Copper locally is important. The area has numerous Sunflower mine workings and have been explored prospects and a few mines and forms part of the Green Valley intermittently in recent years. No quantitative estimates (Payson) mining district. Geologically, area 8 is similar to have been made of the mercury resources of this area, with parts of the Green Valley district to the east, where many the exception of the Sunflower mine at the southwest end of gold deposits are known (Lausen and Wilson, 1925). Although area 9, which is estimated in this study to have inferred entirely outside of the wilderness, the area was examined resources of 26,000 tons of rock containing 0.14 percent briefly because it is mineralized and has some of the same mercury outside the wilderness and 3,600 tons of rock rocks as nearby parts of the wilderness. containing 0.21 percent mercury inside the wilderness. The Gold deposits in area 8 occur as quartz-bearing veins potential for the presence of mercury resources in area 9 is in Proterozoic diorite and included metasedimentary rocks. high. According to Lausen and Wilson (1925) the veins contain free gold and gold in pyrite. The veins are in fault zones of Area 10 westerly and northwesterly trend. Some of the veins show evidence of movement that postdates the mineralization Two areas containing mercury are designated as area (Lausen and Wilson, 1925). In addition to gold, the veins 10 (fig. 3). One surrounds area 9 and extends 0.3 mi into the contain silver and copper. Mazatzal Wilderness. The other part of area 10 is at the The two largest mines in area 8 were examined during southeast margin of the area studied and contains highly this study (Ellis, 1982). The Gowan mine was first worked foliated rocks of approximately the same stratigraphic during the period 1880-1882, but no production data are interval in the Alder Formation as in the northern area. The available for those years (Lausen and Wilson, 1925). The aeromagnetic anomaly mentioned as occurring in area 9 is Gowan mine also produced gold in 1938-1940. The centered close to the southern of the two areas labeled as 10 Crackerjack mine produced gold, silver, and copper during the and extends into the northern area. Both parts of area 10 period 1942-1956. Most of the 17,596 Ib of copper produced contain few prospects and have few mines (Ellis, 1982), all of from the Casterson, Collom, Crackerjack, and Gowan mine which have had little or no production. came from the Crackerjack mine. Assay data from the Mercury is sparsely distributed in area 10. Only rock Gowan and Crackerjack mines show significant values of gold samples from the Story mine showed highly anomalous and silver, and the data from the Crackerjack mine show high concentrations of mercury. Area 10 has a moderate potential copper values (Ellis, 1982). for the occurrence of mercury resources. However, the Our studies suggest that, considering the existence of chances of a deposit the size of the old producing mines in mines that have had production, the large size of area 8, and area 9 are considered small. the extensive soil and forest cover, it is reasonable to assume that the area has a high potential for gold, silver, and copper Area 11 resources in deposits the size of those at the Gowan and Crackerjack mines. Geochemical sampling in the area (not Area 11 contains all exposures of the Alder Formation conducted during this study) would be helpful in estimating outside of areas 9 and 10. Most of the area is in the southern the number and location of any additional deposits. Although part of the Mazatzal Wilderness, but the area extends to the no gold deposits have been found in the dioritic rocks in the west and east of the wilderness boundaries (fig. 3). The only wilderness, faults of westerly and northwesterly trend in indications of mercury in the area are widely scattered these rocks may nevertheless have potential for gold anomalous geochemical concentrations. The potential for resources. mercury resources in the area is low. Areas 9, 10, and 11 mercury Areas 12, 13, and 14 molybdenum About 95 percent of the mercury that has been Indications of molybdenum mineralization found in recovered in Arizona has come from the Sunflower mining stream sediment, heavy-mineral concentrates from stream district (Bailey, 1969), which is centered a few miles east of sediment, rock, and water in the Tangle Creek area west of the southern part of the Mazatzal wilderness. Although the Mazatzal Wilderness during this study suggest that the production from the district has been significant for Arizona, quartz monzonite porphyry exposed west of Tangle Creek it amounts to far less than one percent of the total may contain a porphyry molybdenum resource. Area 12 is the production of mercury in the United States (Bailey, 1969), and exposed part of the quartz monzonite porphyry. Gravity and aeromagnetic data indicate that the quartz monzonite massive sulfide deposits at Jerome, Arizona a porphyry pluton may be moderate in size and may extend reinterpretation: Economic Geology, v. 67, p. 845-863. eastward and northeastward into the roadless area and the Anderson, Phillip, and Guilbert, J. M., 1979, The Precambrian wilderness beneath younger rocks. The outline of area 13 is massive sulfide deposits of Arizona a distinct based on the gravity and aeromagnetic highs that project metallogenic epoch and province, iri Ridge, J. D., ed., southeastward from the vicinity of the outcropping quartz Papers on mineral deposits of western North America, monzonite porphyry. The outline of area 14 is based on weak International Association on the Genesis of Ore gravity and aeromagnetic highs suggestive of the quartz Deposits, Fifth Quadrennial Symposium Proceedings, v. monzonite porphyry at depth and on high molybdenum 2: Nevada Bureau of Mines and Geology Report 33, p. concentrations in a few surface samples. Additional sampling 39-48. will be required in area 12, and drilling will be necessary in Anderson, Phillip, and Wirth, K. R., 1981, Uranium potential areas 13 and 14 to determine the existence, distribution, and in Precambrian conglomerates of the central Arizona grade of any mineralized rocks. On the basis of the meager arch: Final report: Grand Junction, Colo., U.S. data from the geologic reconnaissance and the geochemical Department of Energy Report GJBX-33 (81), 122 p. and geophysical surveys, the potential for the occurrence of Bailey, E. H., 1969, Mercury, in Mineral and water resources molybdenum resources in areas 12, 13, and 14 is low. of Arizona: Arizona Bureau of Mines Bulletin 180, p. 226-230. Areas 15 and 16 tin Beckman, R. T., and Kerns, W. H., 1965, Mercury in Arizona, iri Mercury potential of the United States: U.S. Bureau Evidence of tin mineralization was found during this of Mines Information Circular 8252, p. 60-74. study in the alkali granite in the central part of the Mazatzal Blanchard, Roland, 1968, Interpretation of leached outcrops: Wilderness. Cassiterite identified in heavy-mineral Nevada Bureau of Mines Bulletin 66, p. 7. concentrates of stream-sediment samples collected in this Boyle, R. W., 1979, The geochemistry of gold and its part of the area had to have been derived from the granitic deposits: Canada Geological Survey Bulletin 280, 579 rocks, although none was found in the granite. Moreover, P- greisen zones in the alkali granite appear to be the favored Conway, C. M., 1976, Petrology, structure, and evolution of a host for the tin mineralization. High concentrations of tin, Precambrian volcanic and plutonic complex, Tonto tungsten, beryllium, boron, fluorine, and rare-earth elements Basin, Gila County, Arizona: Pasadena, California in the cassiterite-bearing panned concentrates provide Institute of Technology Ph. D. thesis, 460 p. additional indications of hydrothermal tin mineralization. Conway, C. M., Wrucke, C. T., Ludwig, K. W., and Silver, L. The greisen zones occur in area 15, which is located near the T., 1982, Structures of the Proterozoic Mazatzal center of the wilderness. This is the most favorable area for orogeny, Arizona abs. : Geological Society of tin identified during this study, but it is not certain if the America Abstracts with Programs, v. 14, no. 4, p. 156. abundance of tin is great enough to be indicative of a Ellis, C. E., 1982, Mineral resource potential of the Mazatzal potential for tin resources. Geochemical evidence suggests Wilderness and contiguous RARE n Further Planning that other parts of the alkali granite pluton, labeled as area Areas, Gila, Maricopa, and Yavapai Counties, 16, also may contain greisen zones. However, area 16, like Arizona: U.S. Bureau of Mines Open-File Report MLA area 15, may not have concentrations of tin great enough to 56-82, 12 p. be indicative of a potential for tin resources. Additional Faick, J. N., 1958, Geology of the Ord mine, Mazatzal sampling will be required to identify areas of tin Mountains quicksilver district, Arizona: U.S. concentration and to evaluate more fully the tin resource Geological Survey Bulletin 1042-R, p. R685-R698. potential of the alkali granite. The chances of any part of Grimes, D. J., and Marranzino, A. P., 1968, Direct-current the alkali granite pluton containing recoverable cassiterite arc and alternating current spark emission are extremely poor. No significant concentrations of placer spectrographic field methods for the semiquantitative cassiterite were found. Evidence of tin mineralization has analysis of geologic materials: U.S. Geological Survey not previously been reported as occurring in this rock type in Circular 591, 6 p. Arizona. Hunt, G. R., 1980, Electromagnetic radiation: The communication link in remote sensing, iii Siegal, B. S., Areas 17 and 18 uranium and Gillespie, A. R., Remote sensing in geology: New York, John Wiley and Sons, p. 5-45. Uranium exists in Tertiary tuffs and sedimentary rocks Jones, M. T., Reed, B. L., Doe, B. R., and Lanphere, M. A., near Horseshoe Reservoir, west of the Mazatzal Wilderness. 1977, Age of tin mineralization and plumbotectonics, A large block of claims has been staked in this area outside Belitung, Indonesia: Economic Geology, v. 72, p. 745- the wilderness and partly inside one roadless area (Ellis, 752. 1982). Concentrations of uranium occur in siliceous tuff and Lausen, Carl, and Gardner, E. D., 1927, Quicksilver resources tuffaceous, carbonate-rich Tertiary sandstone northwest and of Arizona: Arizona Bureau of Mines Bulletin 122, 112 southeast of Horseshoe Dam, and in tuffaceous siltstone on P- the east, west, and north sides of Horseshoe Reservoir to Lausen, Carl, and Wilson, E. D., 1925, Gold and copper about 2 mi north of Chalk Mountain. The highest assay value deposits near Payson, Arizona: Arizona Bureau of obtained was 165 ppm uranium oxide from a sample taken Mines Bulletin 120, 44 p. across a 4-in-thick bed southeast of Horseshoe dam (Ellis, Ludwig, K. R., 1973, Precambrian geology of the central 1982). All other values obtained in the same area were 18 Mazatzal Mountains, Arizona: Pasadena, California ppm uranium oxide or less. Area 17, which trends Institute of Technology Ph. D. thesis, 395 p. northwesterly on the south side of the reservoir, has a Madirosian, C. A., 1973, Mining districts and mineral deposits moderate potential for the occurence of uranium resources, of Arizona: Charles A. Madirosian, scale 1:1,000,000. based on the assay concentrations and a favorable host rock. Marsh, S. P., 1983, Arsenic and gold mineralization in the Area 18 has a low potential for the presence of uranium McFarland Canyon Story mine area, Maricopa resources. The proximity of Proterozoic granitic rocks, County, Arizona: U.S. Geological Survey Open-File which are slightly uraniferous, could be a source for some of Report 83-442, 22 p. the uranium in areas 17 and 18. Marsh, S. P., Erickson, M. S., Forn, C. L., and McDougal, C. M., 1983, Spectrographic analyses of panned REFERENCES CITED concentrate from stream-sediment samples from the Mazatzal Wilderness and Mazatzal Wilderness Anderson, C. A., Blacet, P. M., Silver, L. T., and Stern, T. W., Contiguous Roadless Area, Gila, Maricopa, and 1971, Revision of Precambrian stratigraphy in the Yavapai Counties, Arizona: U.S. Geological Survey Prescott-Jerome area, Yavapai County, Arizona: U.S. Open-File Report 83-524, 38 p. Geological Survey Bulletin 1324-C, p. C1-C16. Marsh, S. P., Forn, C., and McDougal, C. M., 1983, Anderson, C. A., and Nash, J. T., 1972, Geology of the Spectrographic analyses and statistical data for stream

10 sediment, panned concentrate from stream sediment, Sauck, W. A., and Summer, J. S., 1970, Residual aeromagnetic and rock samples from the Mazatzal Wilderness and map of Arizona: Tucson, University of Arizona, Mazatzal Wilderness Contiguous Roadless Area, Gila, Department of Geosciences, scale 1:1,000,000. Maricopa, and Yavapai Counties, Arizona: U.S. Silver, L. T., 1967, Apparent age relations in the older Geological Survey Open-File Report 83-197, 38 p. Precambrian stratigraphy of Arizona abs, HI Moore, R. T., and Roseveare, G. H., 1969, Silver, ir^ Mineral Burwasch, R. A., and Morton, R. D., eds., and water resources of Arizona: Arizona Bureau of Geochronology of Precambrian stratified rocks: Mines Bulletin 180, p. 251-270. Edmonton, University of Alberta, p. 87. Ransome, F. L., 1915, Quicksilver deposits of the Mazatzal Taylor, R. G., 1979, Geology of tin deposits: New York, Range, Arizona: U.S. Geological Survey Bulletin 620, Elsevier, 543 p. p. 111-128. U.S. Bureau of Mines and U.S. Geological Survey, 1980, Rowan, L. C., Wetlanfer, P. H., Goetz, A. F. H., Billingsley, Principles of a resource/reserve classification: U.S. F. C., and Stewart, J. H., 1974, Discrimination of rock Geological Survey Circular 831, 5 p. types and detection of hydrothermally altered areas in Wilson, E. D., 1937, Precambrian Mazatzal revolution in south-central Nevada by the use of computer enhanced central Arizona abs. : Geological Society of America ERTS images: U.S. Geological Survey Professional Proceedings, 1936, p. 112-113. Paper 883, 35 p. ___1939, Precambrian Mazatzal revolution in central Sainsbury, C. L., and Reed, B. L., 1973, Tin, in Brobst, D. A., Arizona: Geological Society of America Bulletin, v. and Pratt, W. P., eds., United States mineral 50, p. 1113-1164. resources: U.S. Geological Survey Professional Paper Wilson, E. D., O'Haire, R. T., and McCrory, F. J., 1961, Map 820, p. 637-651. and index of Arizona Mining districts: Arizona Bureau of Mines, scale 1:1,000,000.

11 111 °45 111° 30'

MAZATZAL WILDERNESSc'3'

10 15 MILES

Figure 1. Map showing location of the Mazatzal Wilderness and contiguous roadless area , central Arizona.

12 111045' EXPLANATION

VOLCANIC AND SEDIMENTARY ROCKS CCENOZOIC)

SEDIMENTARY ROCKS [PALEOZOIC) Cvs . MAZATZAL' . 34°15' - QUARTZ MONZONITE CPROTEROZOIC?)

VOLCANIC AND SEDIMENTARY ROCKS CPROTEROZOIC)

CPROTEROZOIC)

34°00' - THRUST FAULT-Sawteeth on upper plate

Figure 2. Map showing generalized geology of the Mazatzal Wilderness and contiguous roadless area. ROADLESS AREA (3-016)

34°20'

MAZATZAL WILDERNESS (NF3048)

Area 14 / (Mo) Area 8 (Au)

Area 4 Area16 (Cu) (Sn)

Area 3 4(Ag.Au,Cu) 5 Area 6 (Cu) Area 12 (Mo)

34°00' y Area 9 - ^ (Hg) Area 17- Area 10 (U) (Hg)

10 MILES J

Figure 3. Areas of mineral resource potential and locations of mines and prospects in the Mazatzal Wilderness and contiguous roadless area. See following page for explanation.

14 EXPLANATION

AREA OF MINERAL RESOURCE POTENTIAL All hachures on mineralized side of line. Copper (Cu) , gold (Au), lead (Pb), mercury (Hg), molybdenum (Mo), silver (Ag), tin (Sn), and uranium (U)

Area 1 High potential for silver, gold, and lead in vein deposits

Area 2 High potential for silver and copper in vein deposits. Low potential for copper in massive sulfide deposits

Area 3 Moderate potential for silver, gold, and copper in vein deposits. Low potential for copper in massive sulfide deposits

Area 4 High potential for copper where exposed copper veins are abundant. Moderate potential for copper where exposed copper veins are not abundant. Low potential for copper in massive sulfide deposits

Area 5 High potential for copper in massive sulfide deposit. Moderate potential for copper in vein deposits

Areas 6 and 7 Low potential for copper in vein deposits or massive sulfide deposits

Area 8 High potential for gold, silver, and copper in vein deposits

Area 9 High potential for mercury in vein deposits

Area 10 Moderate potential for mercury in vein deposits

Area 11 Low potential for mercury in vein deposits

Areas 12, 13, and 14 Low potential for molybdenum in porphyry deposits

Areas 15 and 16 Low(?) potential for tin in greisen zones

Area 17 Moderate potential for uranium in stratabound deposits

Area 18 Low potential for uranium in stratabound deposits

APPROXIMATE BOUNDARY OF WILDERNESS AREA

APPROXIMATE BOUNDARY OF ROADLESS AREA

MINES AND PROSPECT 1. Crackerjack mine 2. Gowan mine 3. House mine 4. Collom mine 5. Casterson mine 6. Stingy Lady prospect 7. Los Conquistadores prospect 8. Blue Lode prospect 9. Gold Creek mine 10. Pine Butte mine 11. Pine Mountain mine 12. Mercuria mine 13. Oneida mine 14. Cornucopia mine 15. Sunflower mine 16. Story mine

15